Steelworkers in Pittsburg once labored in extreme heat in the rolling mill, catching red-hot steel rods with only tongs, cotton gloves, and leather shin guards, but the industry later became identified with manufacturing innovation, modernization, safety, and technology. The local mill opened in 1910 and early supplied the state's gold dredging, shipbuilding, and lumbering industries. The Pittsburg plant became a major force in building the San Francisco Bay Bridge and Hoover Dam, contributed to military production in both world wars, pioneered trade unionism, and continued as the major steel supplier in the West. Steelworkers were vital in the region's economic, social, and civic life, and the mill drew people from every part of the country, helping make Pittsburg a cosmopolitan city known as the Steel City of the West. In 1986, a joint venture between Pohang Iron and Steel of South Korea and U.S. Steel created USS-POSCO Industries, producing a completely refurbished and modernized plant intended to keep steel a vital part of the local economy well into the 21st century.